Quantum dots (QDs) emit narrow-band luminescence that is tunable across the visible spectrum. For this reason, QDs are a cost-effective front-runner among developing down-converting technologies. One class of QDs is core-shell QDs, which can contain two or more distinct semiconductor materials (e.g., CdS and CdSe). Graded alloy core-shell interfaces—interfaces between two materials that vary smoothly from one material to the other—can be used, but synthesis of QDs, including graded core-shell QDs, can be challenging to control and to scale to large quantities. Existing QD synthesis is also limited by two intertwined factors: (1) lack of knowledge concerning the ideal QD structure required for stable luminescence under “on-chip” operating conditions, and (2) poorly understood syntheses that suffer from highly variable reactivity. Both can make it difficult to increase the scale of QD synthesis. Therefore, there is a need for controlled, scalable, reliable processes for preparing compositionally graded nanostructured materials, including graded core-shell QDs.
The present disclosure addresses at least some of these long-felt problems.